Foul odor from vent
My daughters room has a foul odor coming from the vent. The odor comes and goes but seems to get worse as the temperatures are very hot or when the air gets cooler. The floor has been steam cleaned and the ducts have been cleaned as well. The bathroom that is on the first level and directly below her room has the same foul odor from the vents. No other vents have it in our home. It started last year but went away only to return again. I'm not an expert but I first thought plumbing issue but then thought there was a mouse nest somewhere. The basement does not smell but we have caught some mice in the crawl space wall under the bathroom. Anyone have some advice on what to do? The crawl space is insulated.